Indoor navigation with flash drives

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To navigate, you always need location. In the great outdoors, this is no problem thanks to the wonders of GPS. But things can get trickier when you are talking about the interiors of buildings. Times, however, are changing: New flash drives can provide you with centimeter-exact orientation even if you find yourself in the very deepest of basements.

GPS is our trustworthy guide, helping us gain our bearings on unknown streets and in new cities or find the nearest shared bike. But there is a catch, of course: You have to have ready access to the appropriate satellites. In highway tunnels, the navigation system will interpolate without support from the “sky” on the basis of a vehicle’s consistent direction and speed or will be connected to wheel sensors. These sensors measure the rpms of the tires and draw conclusions about the distance already covered.

But just how do robots, driverless transport vehicles and other objects navigate their way inside buildings, warehouses and factories? Instead of GPS satellites, the RTLSflare solutions offered by the Fraunhofer IOSB-AST relies on five flash drives. With the help of this system, objects can be located down to the exact centimeter in real time at a range of up to 100 meters.

Centimeter-exact indoor navigation

The 58x25x10mm flash drives contain a microcontroller, a radio-frequency identification chip, an inertial measurement unit, an USB interface and localization software. Four drives, or flares, are set up throughout a room and create an ad-hoc wireless network. A fifth drive is installed in the mobile device to be located. This is all it takes to locate something in a building in real time and with centimeter precision at a range of 100 meters.

The flash drives transmit ultra-wide band signals (UWB) in the process. When the different propagation times of a signal to different devices installed in a room are measured, software can determine the position on imaginary X, Y and Z axes. But there is a drawback: You have to know the exact position of fixed points in a room to determine the relative position of the mobile device. The process developed by Fraunhofer researchers automatically measures these fixed points. The individual flash drives in the indoor navigation system virtually configure themselves. As a result, they can be flexibly adapted to current applications.

The low-price drives are operated with commercially available power banks or USB power supply units. In the future, the RTLSflares can be used as part of human-machine collaboration in which both a worker and a heavy-load robot are equipped with the devices.

For industrial demonstration purposes, Fraunhofer IOSB-AST offers evaluation kits that consist of five RTLSflares (real time location system), brief instructions and drivers. A set can be tested free of charge for several weeks.

The RTLSflares are also being displayed as part of the special exhibition “Time” at the phaeno Science Center in Wolfsburg. The indoor navigation system is being used to introduce visitors to the secrets of GPS. The exhibition will run through February 3, 2019.

 


Learn more about wireless technologies at the Wireless Congress.

 

 

 

 

Indoor Navigation (Image: Fraunhofer IOSB)

RTLSflares are especially suitable for the geolocation of mobile robots and automatic guided vehicles in logistics. (Image: Fraunhofer IOSB).